AlGaN/GaN heterostructure grown on 1∘-tilt sapphire substrate by MOCVD

AlGaN/GaN epitaxial layers were grown on 0^{{ring operator}}-tilt and 1^{{ring operator}}-tilt sapphire substrates by metalorganic chemical vapor deposition (MOCVD). With exactly the same growth conditions, it was found that dislocation density was smaller and crystal quality was better for the AlGaN/GaN epitaxial layers prepared on 1^{{ring operator}}-tilt sapphire substrate. We also found that AlGaN/GaN epitaxial layers on 1^{{ring operator}}-tilt sapphire substrate were grown with step growth mode while those on 0^{{ring operator}}-tilt substrate were grown with two-dimensional island growth. From the temperature-dependent mobility, it was found that crystal quality of the AlGaN/GaN epitaxial layer prepared on 1^{{ring operator}}-tilt sapphire substrate is better.